1. Field of the Invention
The invention relates to a calender with two separately operating roll stacks, each roll stack including a top roll composed of a deflection compensation roll and a bottom roll composed of a deflection compensation roll.
2. Discussion of Background Information
A calender similar in general to the above-described calender is discussed, e.g., in German Patent Application 195 08 353. Calenders of this type have been shown to be advantageous in that a material web, e.g., a paper web, is treated on both sides with practically the same results. The total number of rolls in these devices is kept lower than the number utilized in conventional multi-roll calenders, which is typically equipped with twelve rolls. Further, the control of compressive strains in individual nips is carried out with a higher degree of freedom.
However, when the calender is embodied with two separately operable roll stacks, additional space for housing the calender is required. Further, two additional calender stanchions or mounting brackets are necessary, which, as discussed in above-noted German Patent Application 195 08 353, are positioned so that the roll plane, i.e. planes formed by the axes of the rolls in a particular roll stack, for each roll stack is positioned parallel to and spaced apart from each other to form neighboring roll stacks. This results in increased investment costs, and, in some cases, retrofitting is not possible due to a limited amount of available space.